I have a question regarding implementation of the MPI_MODE_NOCHECK assertion for MPI_WIN_LOCK. Is current mpich implementation taking advantage of this hint? Also, according to the standard: MPI_MODE_NOCHECK - no other process holds, or will attempt to acquire, a conflicting lock, while the caller holds the window lock. This is useful when mutual exclusion is achieved by other means, but the coherence operations that may be attached to the lock and unlock calls are still required. Are two concurrent locks from two different MPI processes followed by MPI_GET (i.e. given window is not modified but read only) considered conflicting? Thanks! - Jaric